KR102586249B1 - Imaging element and electronic equipment - Google Patents

Abstract

This technology relates to imaging elements and electronic devices that enable better images to be obtained. In an imaging device having a plurality of pixels, the pixel has one on-chip lens and a plurality of photoelectric conversion layers formed lower than the on-chip lens, and at least two photoelectric conversion layers among the plurality of photoelectric conversion layers are , each of which is divided, partially formed, or partially shaded with respect to the light receiving surface. The pixel is a phase detection pixel for performing AF by phase difference detection, or an imaging pixel for generating an image. This technology can be applied to CMOS image sensors, for example.

Description

IMAGING ELEMENT AND ELECTRONIC EQUIPMENT}

This technology relates to imaging devices and electronic devices, and in particular, to imaging devices and electronic devices that enable better images to be obtained.

In recent years, an imaging device that performs phase difference detection by providing a phase difference detection pixel in which a part of the photoelectric conversion unit is light-shielded has been known (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2010-160313

However, in a phase detection pixel, a part (for example, half) of the photoelectric conversion part is shaded, so the sensitivity is lower than that of a normal imaging pixel, and in a low-light environment, a sufficient SNR (Signal-Noise Ratio) is not obtained, and accurate There is a risk that phase difference detection may not be performed. As a result, it is out of focus and blurred; There is a possibility that a burn may occur.

Additionally, in normal imaging pixels, there is a risk that color mixing from adjacent pixels may adversely affect color reproducibility and SNR.

This technology was developed in consideration of such situations, and is intended to enable better images to be obtained.

An imaging device according to one aspect of the present technology is an imaging device including a plurality of pixels, wherein the pixel includes one on-chip lens, a plurality of photoelectric conversion layers formed lower than the on-chip lens, and a plurality of pixels. At least two of the photoelectric conversion layers are each formed separately, partially formed, or partially shielded from light with respect to the light-receiving surface.

The pixel can be used as a phase detection pixel for performing AF (Auto Focus) by phase difference detection.

The difference in output between the photoelectric conversion layers in the plurality of phase difference detection pixels can be used for phase difference detection.

Imaging pixels for generating images may also be provided, and the phase difference detection pixels may be arranged interspersed among the plurality of imaging pixels arranged two-dimensionally in a matrix.

The difference between the outputs of the photoelectric conversion layer in the phase difference detection pixel and the imaging pixel arranged around the phase difference detection pixel can be used for phase difference detection.

In the phase difference detection pixel, an organic photoelectric conversion film partially formed as the uppermost photoelectric conversion layer among the plurality of photoelectric conversion layers, and a photoelectric conversion layer formed on a substrate lower than the organic photoelectric conversion film, A photoelectric conversion unit that is partially shaded can be provided.

In the phase difference detection pixel, a light-shielding film that partially blocks the photoelectric conversion unit is further provided under the organic photoelectric conversion film, and light partially blocked by the light-shielding film can be photoelectrically converted to the organic photoelectric conversion film.

In the phase difference detection pixel, as the plurality of photoelectric conversion layers, at least two layers of divided photoelectric conversion parts formed on a substrate can be provided.

In the phase difference detection pixel, at least two layers of organic photoelectric conversion films that are divided or partially shielded can be provided as the plurality of photoelectric conversion layers.

The pixel can be used as an imaging pixel for generating an image.

The imaging pixel includes an organic photoelectric conversion film partially formed as the uppermost photoelectric conversion layer among the plurality of photoelectric conversion layers, and an adjacent photoelectric conversion layer formed on a substrate lower than the organic photoelectric conversion film. A photoelectric conversion unit whose boundary with another imaging pixel is partially shielded from light may be provided, and the organic photoelectric conversion film may be formed at the boundary with the other imaging pixel.

The phase difference detection pixel may be provided with a plurality of photoelectric conversion layers, such as an organic photoelectric conversion film and a photoelectric conversion unit formed on a substrate, and the organic photoelectric conversion film and the photoelectric conversion unit may be controlled to have different exposure amounts. there is.

An electronic device according to one aspect of the present technology is an imaging device having a plurality of pixels, wherein the pixel includes one on-chip lens, a plurality of photoelectric conversion layers formed lower than the on-chip lens, and a plurality of pixels. At least two of the photoelectric conversion layers include an imaging element that is divided, partially formed, or partially shielded from the light-receiving surface, and a lens that makes subject light incident on the imaging element.

A phase difference detection unit that detects the phase difference using the difference in output between the photoelectric conversion layers in the plurality of pixels and a lens control unit that controls driving of the lens in response to the detected phase difference can also be provided.

The pixel includes an organic photoelectric conversion film partially formed as the uppermost photoelectric conversion layer among the plurality of photoelectric conversion layers, and the photoelectric conversion layer formed on a substrate lower than the organic photoelectric conversion film, partially blocking light. A photoelectric conversion unit can be provided.

Using the output of the organic photoelectric conversion film, a defect correction unit that corrects the output of the photoelectric conversion unit as pixel values for generating an image can also be provided.

The pixel includes a partially formed organic photoelectric conversion film as the uppermost photoelectric conversion layer among the plurality of photoelectric conversion layers, and an adjacent photoelectric conversion layer as the photoelectric conversion layer formed on a substrate lower than the organic photoelectric conversion film. A photoelectric conversion unit whose boundary with other pixels is partially shielded from light may be provided, and the organic photoelectric conversion film may be formed at the boundary with the other pixels.

Using the output of the organic photoelectric conversion film, a color mixing subtractor that subtracts a color mixing component from the output of the photoelectric conversion unit as pixel values for generating an image can also be provided.

A light source estimation unit that estimates the light source of the subject light can also be provided using the outputs of the plurality of photoelectric conversion layers having different spectral characteristics.

Based on the estimation result of the light source estimation unit, a color characteristics correction unit that corrects the color characteristics of the pixel value output from the photoelectric conversion unit may also be provided.

In one aspect of the present technology, at least two photoelectric conversion layers among the plurality of photoelectric conversion layers are each formed separately, partially formed, or partially shielded from light with respect to the light receiving surface.

According to one aspect of the present technology, it becomes possible to obtain better images.

1 is a block diagram showing a configuration example of an imaging device according to a first embodiment of the present technology.
2 is a diagram explaining the pixel arrangement of the imaging device.
3 is a cross-sectional view showing a structural example of a phase difference detection pixel of the present technology.
4 is a diagram comparing a conventional phase difference detection pixel and the phase difference detection pixel of the present technology.
5 is a flow chart explaining AF processing.
6 is a flow chart explaining image pickup processing.
Fig. 7 is a diagram explaining a conventional defect correction method.
Fig. 8 is a cross-sectional view showing another structural example of a phase difference detection pixel.
Fig. 9 is a cross-sectional view showing another structural example of a phase difference detection pixel.
Fig. 10 is a cross-sectional view showing another structural example of a phase difference detection pixel.
Fig. 11 is a cross-sectional view showing another structural example of a phase difference detection pixel.
Fig. 12 is a cross-sectional view showing another structural example of a phase difference detection pixel.
Fig. 13 is a cross-sectional view showing another structural example of a phase difference detection pixel.
Fig. 14 is a cross-sectional view showing another structural example of a phase difference detection pixel.
Fig. 15 is a cross-sectional view showing another structural example of a phase difference detection pixel.
Fig. 16 is a cross-sectional view showing another structural example of a phase difference detection pixel.
Fig. 17 is a block diagram showing a configuration example of an imaging device according to the second embodiment of the present technology.
Fig. 18 is a cross-sectional view showing a structural example of an imaging pixel of the present technology.
Fig. 19 is a diagram showing a configuration example of an organic photoelectric conversion film.
20 is a diagram comparing a conventional imaging pixel and an imaging pixel of the present technology.
Fig. 21 is a flow chart explaining imaging processing.
Fig. 22 is a block diagram showing a configuration example of an imaging device according to the third embodiment of the present technology.
Fig. 23 is a flow chart explaining imaging processing.
Fig. 24 is a block diagram showing another configuration example of an imaging device.
Fig. 25 is a cross-sectional view showing a structural example of a mixed color detection pixel and an imaging pixel.
Fig. 26 is a block diagram showing a configuration example of an imaging device according to the fourth embodiment of the present technology.

Hereinafter, embodiments of the present technology will be described with reference to the drawings. In addition, the explanation is carried out in the following order.

1. First embodiment (configuration for performing phase difference detection and defect correction)

2. Second embodiment (configuration for performing color mixing subtraction)

3. Third embodiment (configuration for performing color mixing subtraction and light source estimation)

4. Fourth Embodiment (Configuration Equipped with Two Imaging Elements)

<1. First embodiment>

[Configuration of imaging device]

1 is a diagram showing a configuration example of an imaging device according to a first embodiment of the present technology. The imaging device 100 shown in FIG. 1 is a device that captures an image of a subject by performing AF (Auto Focus) (phase difference AF) of the phase difference detection method and outputs the image of the subject as an electrical signal.

The imaging device 100 shown in FIG. 1 includes a lens 101, an optical filter 102, an imaging element 103, an A/D conversion unit 104, a clamp unit 105, a phase difference detection unit 106, Lens control unit 107, defect correction unit 108, demosaicing unit 109, linear matrix (LM)/white balance (WB)/gamma correction unit 110, luminance chroma signal generation unit 111, and interface. It consists of (I/F) part 112.

The lens 101 adjusts the focal length of the subject light incident on the imaging device 103. At the rear end of the lens 101, an aperture (not shown) is provided to adjust the amount of subject light incident on the imaging device 103. The specific configuration of the lens 101 is arbitrary, and for example, the lens 101 may be composed of a plurality of lenses.

The object light that passes through the lens 101 enters the imaging device 103 through the optical filter 102, which is configured as, for example, an IR cut filter that transmits light other than infrared light.

The imaging element 103 includes a plurality of pixels having photoelectric conversion elements such as photodiodes that photoelectrically convert object light. Each pixel converts object light into an electrical signal. The imaging element 103 may be, for example, a CCD image sensor in which a photoelectric conversion element reads charges generated from light and transmits them using a circuit element called a charge coupled device (CCD). A CMOS image sensor using CMOS (Complementary Metal Oxide Semiconductor) and having an amplifier for each unit cell may also be used.

The imaging element 103 has a color filter for each pixel on the subject side of the photoelectric conversion element. As for the color filter, filters of each color, such as red (R), green (G), and blue (B), are arranged on each photoelectric conversion element in, for example, a Bayer array. That is, the imaging element 103 photoelectrically converts the subject light of each color that has passed through the filter and supplies the electrical signal to the A/D conversion unit 104.

The color of the color filter of the imaging device 103 is arbitrary, and may include colors other than RGB, or some or all of the RGB colors may not be used. Additionally, the arrangement of each color is arbitrary, and an arrangement other than the Bayer arrangement may be used. For example, as an arrangement of the color filter of the imaging element 103, an arrangement including white pixels (described in Japanese Patent Application Laid-Open No. 2009-296276) or emerald pixels, a clear bit arrangement, etc. may be applied.

Additionally, the imaging element 103 includes a pixel (imaging pixel) that generates a signal for generating an image based on the received object light, and a pixel (phase difference detection pixel) that generates a signal for performing AF by phase difference detection. ) is placed.

FIG. 2 shows an example of pixel arrangement of the imaging device 103.

As shown in FIG. 2, in the imaging element 103, a plurality of imaging pixels shown as white squares are two-dimensionally arranged in a matrix. The imaging pixel consists of an R pixel, a G pixel, and a B pixel, and these are regularly arranged according to a Bayer arrangement.

Additionally, in the imaging element 103, a plurality of phase difference detection pixels shown in black squares are arranged interspersed among a plurality of imaging pixels arranged two-dimensionally in a matrix. The phase difference detection pixels are regularly arranged in a specific pattern by replacing some of the predetermined imaging pixels in the imaging element 103. In the example of FIG. 2, the two G pixels are replaced with phase difference detection pixels P1 and P2. Additionally, the phase difference detection pixels may be arranged irregularly in the imaging element 103. If the phase difference detection pixels are arranged regularly, signal processing such as defect correction, which will be described later, can be facilitated. If the phase difference detection pixels are arranged irregularly, artifacts caused by defect correction will also be irregular, which will reduce their visibility. You can (make it unnoticeable).

Returning to the explanation of FIG. 1, the A/D conversion unit 104 converts the RGB electrical signals (analog signals) supplied from the imaging device 103 into digital data (image data). The A/D conversion unit 104 supplies image data (RAW data) of the digital data to the clamp unit 105.

The clamp unit 105 subtracts the black level, which is the level determined to be black, from the image data. The clamp unit 105 supplies the image data output from the phase difference detection pixel to the phase difference detection unit 106 among the image data from which the black level has been subtracted. Additionally, the clamp unit 105 supplies all pixels of the image data with the black level subtracted to the defect correction unit 108.

That is, only the output of the phase difference detection pixel is used for phase difference detection, but for image generation, not only the output of the imaging pixel but also the output of the phase difference detection pixel is used.

The phase difference detection unit 106 determines whether the object to be focused (in-focus object) is in focus by performing phase difference detection processing based on the image data from the clamp unit 105. . When an object in the focus area is in focus, the phase difference detection unit 106 supplies information indicating that it is in focus to the lens control unit 107 as an in-focus determination result. In addition, the phase difference detection unit 106 calculates the amount of out-of-focus (defocus amount) when the in-focus object is out of focus, and uses information indicating the calculated defocus amount as the in-focus determination result of the lens control unit ( 107).

The lens control unit 107 controls the driving of the lens 101. Specifically, the lens control unit 107 calculates the driving amount of the lens 101 based on the in-focus determination result supplied from the phase difference detection unit 106, and moves the lens 101 in response to the calculated driving amount. I order it.

For example, when the lens control unit 107 is in focus, it maintains the current position of the lens 101. In addition, when the lens control unit 107 is out of focus, the lens control unit 107 calculates a driving amount based on the in-focus determination result indicating the defocus amount and the position of the lens 101, and moves the lens 101 according to the driving amount. Move it.

Additionally, the lens control unit 107 may control the driving of the lens 101 by performing contrast AF in addition to the phase difference AF as described above. For example, when information indicating the amount of focus misalignment (defocus amount) is supplied from the phase difference detection unit 106 as an in-focus determination result, the lens control unit 107 operates in the direction of focus misalignment (previous). It is also possible to determine whether it is a pin or a post-pin and perform contrast AF in that direction.

The defect correction unit 108 corrects the pixel value of a defective pixel for which a correct pixel value cannot be obtained, that is, performs defect correction, based on the image data from the clamp unit 105. The defect correction unit 108 supplies image data on which defective pixels have been corrected to the demosaicing unit 109.

The demosaicing unit 109 performs demosaicing processing on the RAW data from the defect correction unit 108, supplements color information, etc., and converts it into RGB data. The demosaicing unit 109 supplies image data (RGB data) after demosaicing processing to the LM/WB/gamma correction unit 110.

The LM/WB/gamma correction unit 110 corrects color characteristics of the RGB data from the demosaicing unit 109. Specifically, the LM/WB/gamma correction unit 110 uses matrix coefficients to compensate for each color of the image data in order to make up for the difference between the chromaticity point of the primary colors (RGB) specified in the standard and the chromaticity point of the actual camera. Processing is performed to correct the signal and change color reproducibility. Additionally, the LM/WB/gamma correction unit 110 adjusts the white balance by setting a gain for white for the value of each channel of RGB data. Additionally, the LM/WB/gamma correction unit 110 adjusts the relative relationship between the color of the image data and the output device characteristics and performs gamma correction to obtain a display closer to the original. The LM/WB/gamma correction unit 110 supplies the corrected image data (RGB data) to the luminance chroma signal generation unit 111.

The luminance chroma signal generator 111 generates a luminance signal (Y) and color difference signals (Cr, Cb) from RGB data supplied from the LM/WB/gamma correction unit 110. When the luminance chroma signal generation unit 111 generates luminance chroma signals (Y, Cr, Cb), it supplies the luminance signal and the color difference signal to the I/F unit 112.

The I/F unit 112 transmits the supplied image data (luminance chroma signal) to the outside of the imaging device 100 (for example, a storage device that stores the image data or a display device that displays an image of the image data). etc.).

[Structure example of phase detection pixel]

Fig. 3 is a cross-sectional view showing a structural example of a phase difference detection pixel of the present technology. Moreover, in FIG. 3, the phase difference detection pixels P1 and P2 are shown as being arranged adjacent to each other, but as shown in FIG. 2, they may be arranged with a predetermined number of imaging pixels sandwiched between them.

As shown in FIG. 3, in the phase detection pixels P1 and P2, a photodiode 122 as a photoelectric conversion unit is formed on a semiconductor substrate (Si substrate) 121. In the upper layer of the semiconductor substrate 121, a light-shielding film 123 and a color filter 124 are formed in the same layer, and their upper layer, specifically, directly above the light-shielding film 123, has an area that is approximately the same as that of the light-shielding film 123. The organic photoelectric conversion film 125 is formed. Additionally, an on-chip lens 126 is formed on the organic photoelectric conversion film 125.

The light-shielding film 123 may be made of metal or may be a black filter that absorbs light. Additionally, the light-shielding film 123 may be formed of electrodes of the organic photoelectric conversion film 125. In this case, since the wiring layer can be reduced, the imaging element 103 can be reduced in size, and further, the sensitivity of the photodiode 122 can be improved.

The color filter 124 may be the same color as the phase difference detection pixel P1 and the phase difference detection pixel P2, or may be of different colors. Additionally, when the phase difference detection pixels P1 and P2 are white pixels, the color filter 124 may not be provided.

The organic photoelectric conversion film 125 photoelectrically converts light of a specific wavelength. For example, the organic photoelectric conversion film 125 photoelectrically converts light of any of the three colors of red, green, and blue.

As an organic photoelectric conversion film that photoelectrically converts green light, for example, an organic photoelectric conversion material containing a rhodamine-based dye, a merocyanine-based dye, quinacridone, etc. can be used. As an organic photoelectric conversion film that photoelectrically converts red light, an organic photoelectric conversion material containing a phthalocyanine-based pigment can be used. As an organic photoelectric conversion film that photoelectrically converts blue light, an organic photoelectric conversion material containing a coumarin-based dye, lys-8-hydroxyquinoline Al(Alq3), a merocyanine-based dye, etc. can be used.

In addition, the organic photoelectric conversion film 125 is not limited to visible light such as red, green, and blue, and may be configured to photoelectrically convert white light, infrared light, or ultraviolet light.

Each phase detection pixel shown in FIG. 3 includes one on-chip lens 126 and a plurality of photoelectric conversion layers formed lower than the on-chip lens 126, specifically, an organic photoelectric conversion film (from the upper layer) 125) and a photodiode 122. Here, if the surface on which the on-chip lens 126 is formed is defined as the light-receiving surface per pixel, the organic photoelectric conversion film 125 is partially formed with respect to the light-receiving surface (hereinafter referred to as partially formed). . In addition, the photodiode 122 is partially (for example, half) shielded from light by the light shielding film 123 (hereinafter referred to as partially shielded).

In addition, in FIG. 3, the phase difference detection pixels P1 and P2 have a left-shading and right-shading configuration, respectively. However, depending on the arrangement of each pixel, they may be configured to have an upper light-shielding and lower-side light-shading configuration, and can be detected at an angle. It may be shaded from light.

Next, with reference to FIG. 4, the structures of the conventional phase difference detection pixel and the phase difference detection pixel of the present technology are compared.

The conventional phase difference detection pixel shown on the left side of FIG. 4 differs from the phase difference detection pixel of the present technology shown on the right side of FIG. 4 in that the organic photoelectric conversion film 125 is not provided.

According to the structure of a conventional phase detection pixel, a part of the incident light L1 is reflected by the light shielding film 123 of the pixel on the left and then diffusely reflected within the imaging element 103, so that a part of the incident light R1 is also reflected. After being reflected on the light shielding film 123 of the pixel on the right, there is a possibility that flare or color mixing in adjacent pixels may occur due to diffuse reflection within the imaging element 103.

Additionally, in the conventional phase difference detection pixel, since half of the photo diode 122 is shielded from light by the light shielding film 123, there is a risk that sufficient SNR cannot be obtained in a low-light environment and phase difference detection may not be performed accurately.

In addition, as described above, the output of the phase difference detection pixel is also used to generate an image, but for the reasons described above, the output of the phase difference detection pixel is smaller than the output of the imaging pixel, so the output of the phase difference detection pixel is: It is necessary to correct it based on the output of the surrounding imaging pixels.

On the other hand, according to the structure of the phase detection pixel of the present technology, part of the incident light L1 is partially absorbed and transmitted by the organic photoelectric conversion film 125 of the left pixel, is reflected on the light shielding film 123, and then is again converted to organic photoelectric conversion. It is absorbed in the conversion film 125. Similarly, part of the incident light R1 is absorbed and transmitted by the organic photoelectric conversion film 125 of the pixel on the right, is reflected by the light blocking film 123, and is then absorbed by the organic photoelectric conversion film 125 again. Therefore, diffuse reflection of incident light within the imaging device 103 can be suppressed, and occurrence of flare or color mixing in adjacent pixels can be prevented.

In addition, in the phase detection pixel of the present technology, incident light that has been conventionally blocked is photoelectrically converted by the organic photoelectric conversion film 125, so in addition to the output of the photodiode 122, the output of the organic photoelectric conversion film 125 can be obtained. As a result, sufficient SNR can be obtained even in a low-light environment, and phase difference detection can be performed accurately.

In addition, the incident light that passes through the organic photoelectric conversion film 125 and is reflected by the light shielding film 123 re-enters the organic photoelectric conversion film 125, thereby increasing the efficiency of photoelectric conversion in the organic photoelectric conversion film 125. You can. Thereby, it is possible to further improve the precision of phase difference detection. In addition, if sufficient output is obtained even if the thickness of the organic photoelectric conversion film 125 is thinned, the imaging element 103 can be reduced in height, and further, the sensitivity of the photodiode 122 can be improved. there is.

Additionally, since the output of the organic photoelectric conversion film 125 can be obtained in addition to the output of the photodiode 122, there is no need to correct the output of the phase difference detection pixel based on the output of the imaging pixels around it.

[About phase detection AF processing]

Here, with reference to the flow chart in FIG. 5, phase difference AF processing by the imaging device 100 will be described. Phase difference AF processing is performed before imaging processing performed by the imaging device 100 when imaging a subject.

First, in step S101, the imaging element 103 photoelectrically converts the incident light at each pixel, reads each pixel signal, and supplies it to the A/D conversion unit 104.

In step S102, the A/D conversion unit 104 performs A/D conversion on each pixel signal from the imaging device 103 and supplies it to the clamp unit 105.

In step S103, the clamp unit 105 determines the black level detected in the OPB (Optical Black) area provided outside the effective pixel area from each pixel signal (pixel value) from the A/D conversion unit 104. Subtract. The clamp unit 105 supplies the image data (pixel value) output from the phase difference detection pixel to the phase difference detection unit 106 among the image data from which the black level has been subtracted.

In step S104, the phase difference detection unit 106 performs in-focus determination by performing phase difference detection processing based on the image data from the clamp unit 105. The phase difference detection process is performed using the difference in output between pixels that block light from opposite light-receiving surfaces, such as the phase difference detection pixels P1 and P2 shown in FIG. 4, for example.

Conventionally, assuming that the outputs of the photodiodes 122 in the conventional phase difference detection pixels P1 and P2 shown on the left side of FIG. 4 are respectively PhasePixel_P1 and PhasePixel_P2, the detected phase difference (Phase_Diff) is, for example, the following equation ( It is obtained by 1) and (2).

[Formula 1]

[Formula 2]

Meanwhile, in the present technology, the outputs of the photodiodes 122 in the phase detection pixels P1 and P2 of the present technology shown on the right side of Figure 4 are respectively PhasePixel_P1 and PhasePixel_P2, and the outputs of the organic photoelectric conversion film 125 are respectively PhasePixel_Organic1. , PhasePixel_Organic2, the detected phase difference (Phase_Diff) is obtained, for example, by the following equations (3), (4), and (5).

[Formula 3]

[Formula 4]

[Formula 5]

In addition, in this technology, the difference (Phase_Diff_A) of the output of the photodiode 122 of the phase difference detection pixel (P1, P2) and the phase difference detection pixel (P1, P2) are calculated according to the following equations (6) and (7). The difference (Phase_Diff_B) of the output of the organic photoelectric conversion film 125 may be determined and the accuracy of each may be determined, so that either Phase_Diff_A or Phase_Diff_B may be used as the phase difference.

[Formula 6]

[Formula 7]

In addition, in the above-mentioned equations (3) to (7), PhasePixel_P1, PhasePixel_P2 and PhasePixel_Organic1, PhasePixel_Organic2 are the values of the output of the photodiode 122 and the organic photoelectric conversion film 125 of each of the phase detection pixels (P1 and P2). Although it is said to be as is, it may be used as a value where gain is given to each output using a predetermined coefficient. In addition, the phase difference obtained using the output of the photodiode 122 and the organic photoelectric conversion film 125 of each of the phase difference detection pixels P1 and P2 is obtained by the above-mentioned equations (3) to (7). It is not limited, and may be obtained by applying other operations.

In this way, in the conventional phase difference detection pixel, only the photodiode 122 of each of the two pixels can be used for phase difference detection, but in the phase difference detection pixel of the present technology, the photodiode 122 of each of the two pixels is used for phase difference detection. In addition to the output of ), the output of each organic photoelectric conversion film 125 can be used.

When the phase difference detection process is performed in this way and the in-focus determination is made, the phase difference detection unit 106 supplies the in-focus determination result to the lens control unit 107.

In step S105, the lens control unit 107 controls the driving of the lens 101 based on the in-focus determination result from the phase difference detection unit 106.

According to the above processing, in addition to the output of each photodiode 122 of each of the two pixels, the output of each organic photoelectric conversion film 125 can be used for phase difference detection, so the amount of signal used for phase difference detection can be increased. . As a result, sufficient SNR can be obtained even in a low-light environment, phase difference detection can be performed accurately, and as a result, it is possible to obtain a better image that is not out of focus.

[About image capture processing]

Next, with reference to the flow chart in FIG. 6, imaging processing by the imaging device 100 will be described.

Here, since the processing of steps S201 to S203 in the flowchart of FIG. 6 is the same as the processing of steps S101 to S103 in the flowchart of FIG. 5, the description thereof is omitted. Additionally, in step S203, image data (pixel values) for all pixels from which the black level has been subtracted is supplied to the defect correction unit 108 by the clamp unit 105.

In step S204, the defect correction unit 108 performs correction (defect correction) of the pixel value of a defective pixel for which a correct pixel value cannot be obtained, that is, a phase difference detection pixel, based on the image data from the clamp unit 105. do it

In the conventional phase difference detection pixel, only the output of the light-shielded photodiode 122 can be obtained as the output (pixel value), so as a method of correcting the defect, as shown in FIG. 7, phase difference detection of the correction target is performed. The output of the phase difference detection pixel P is replaced based on the output of pixels of the same color surrounding the pixel P, etc.

However, in the above-described method, the original pixel value of the phase difference detection pixel P is completely ignored by replacing the pixel value to be corrected with a value based on the output of the surrounding pixel. This is equivalent to a decrease in resolution, and may result in deterioration of image quality.

On the other hand, in the phase difference detection pixel of the present technology, the output of the organic photoelectric conversion film 125 can be obtained as the output (pixel value) in addition to the output of the light-shielded photodiode 122. Therefore, by using the output of the organic photoelectric conversion film 125 to estimate the output corresponding to the blocked light, the pixel value P1_Out of the phase difference detection pixel P1 after defect correction is calculated, for example, by the following equation. Obtained by (8).

[Formula 8]

Additionally, in equation (8), α and β are coefficients determined according to the difference in sensitivity between the photodiode 122 and the organic photoelectric conversion film 125.

According to equation (8), since the pixel value of the original phase difference detection pixel P1 can be used as the pixel value to be corrected, a decrease in resolution can be suppressed, and it becomes possible to achieve higher image quality.

In addition, the pixel value of the phase difference detection pixel after defect correction is not limited to being obtained by the above-mentioned equation (8), and may be obtained by applying another calculation.

Image data for which defective pixels have been corrected in this way is supplied to the demosaicing unit 109.

In step S205, the demosaicing unit 109 performs demosaicing processing to convert RAW data into RGB data and supplies it to the LM/WB/gamma correction unit 110.

In step S206, the LM/WB/gamma correction unit 110 performs color correction, white balance adjustment, and gamma correction on the RGB data from the demosaicing unit 109, and produces a luminance chroma signal generation unit 111. ) is supplied to.

In step S207, the luminance chroma signal generating unit 111 generates a luminance signal and a color difference signal (YCrCb data) from RGB data.

Then, in step S208, the I/F unit 112 outputs the luminance signal and the chrominance signal generated by the luminance chroma signal generation unit 111 to an external recording device or display device, and ends the imaging process.

According to the above processing, in correcting defects of the phase difference detection pixel, the output corresponding to the blocked light can be estimated and the pixel value of the original phase difference detection pixel can be used, thereby suppressing the decrease in resolution and improving the image quality. This makes it possible to obtain better images.

However, in the phase detection pixel shown in FIG. 3, when the attenuation rate of light of the wavelength photoelectrically converted by the organic photoelectric conversion film 125 (transmission wavelength of the color filter 124) is sufficient, as shown in FIG. 8, Of the light-shielding film 123, the part that blocks half of the photodiode 122 may be omitted.

According to this structure, diffuse reflection due to light reflected by the light shielding film 123 can be suppressed, and occurrence of flare or color mixing in adjacent pixels can be prevented. Additionally, if the light-shielding film 123 is not provided at all, the manufacturing process can be reduced.

Additionally, the organic photoelectric conversion film 125 may be provided lower than the light-shielding film 123 or the color filter 124.

In addition, in the above, it is assumed that phase difference detection is performed using the difference between the photoelectric conversion layers (photodiode 122 and organic photoelectric conversion film 125) in the phase difference detection pixel, but the photoelectric conversion layer in the phase difference detection pixel Phase difference detection may be performed using the difference between the output of and the output of the imaging pixels arranged around the phase difference detection pixel.

[Other structural examples of phase detection pixels]

Fig. 9 is a cross-sectional view showing another structural example of a phase difference detection pixel of the present technology.

The cross-sectional view of FIG. 9 is different from the cross-sectional view of FIG. 3 in that the imaging pixels P2 and P3 are arranged between the phase difference detection pixels P1 and P4, and the color filter 124 is positioned between the light-shielding film 123. ), but is formed on the upper layer of the organic photoelectric conversion film 125.

When the imaging element 103 has a pixel with the structure shown in FIG. 9, phase difference detection processing is performed using the output of the phase difference detection pixel and the output of the adjacent imaging pixel.

Specifically, by the following equations (9) to (11), the difference (Phase_Diff_A) of the output of the organic photoelectric conversion film 125 of the phase difference detection pixels P1 and P4, the imaging pixel P2 and the phase difference detection pixel The difference (Phase_Diff_B) of the output of the photodiode 122 of (P1) and the difference (Phase_Diff_C) of the output of the photodiode 122 of the imaging pixel (P3) and the phase difference detection pixel (P4) are obtained, and for each By performing a predetermined calculation, the final phase difference is obtained.

[Formula 9]

[Formula 10]

[Formula 11]

In addition, α in Equation (10) and β in Equation (11) are coefficients determined in response to the sensitivity lowered by the light blocking by the light shielding film 123 in the phase difference detection pixels P1 and P4.

In this way, in the phase difference detection process, not only the difference between the outputs of the phase difference detection pixels, but also the difference between the output of the photoelectric conversion layer in the phase difference detection pixel and the output of the imaging pixels arranged around the phase difference detection pixel can be used. there is.

[Another structural example of a phase detection pixel]

Fig. 10 is a cross-sectional view showing another structural example of a phase difference detection pixel of the present technology.

In the phase detection pixel shown in FIG. 10, photodiodes 131-1 to 131-4 as photoelectric conversion units are formed on the semiconductor substrate 121. Organic photoelectric conversion films 132-1 and 132-2 are formed on the upper layer of the semiconductor substrate 121. Additionally, an on-chip lens 126 is formed on the organic photoelectric conversion films 132-1 and 132-2.

Each phase detection pixel shown in FIG. 10 includes one on-chip lens 126 and a plurality of photoelectric conversion layers formed lower than the on-chip lens 126, specifically, an organic photoelectric conversion film (from the upper layer) 132-1, 132-2) and photodiodes (131-1 to 131-4). The organic photoelectric conversion films 132-1 and 132-2 are formed dividedly with respect to the light-receiving surface (hereinafter referred to as dividedly formed). Additionally, the photodiodes 131-1 to 131-4 are formed in two layers in the cross-sectional height direction, and are formed separately in each layer.

Additionally, a method of forming a plurality of photodiodes in the cross-sectional height direction is disclosed, for example, in Japanese Patent Application Laid-Open No. 2011-29337 and Japanese Patent Application Laid-Open No. 2011-40518.

In the phase detection pixel shown in FIG. 10, each photoelectric conversion layer, that is, the uppermost organic photoelectric conversion film 132-1 and 132-2, and the photodiode 131-1 and 131- in the second layer from the top. 2) The photodiodes 131-3 and 131-4 in the third layer from the top photoelectrically convert light of different wavelengths. For example, the organic photoelectric conversion films 132-1 and 132-2 photoelectrically convert green light, the photodiodes 131-1 and 131-2 photoelectrically convert blue light, and the photodiode 131 -3, 131-4) converts red light into photoelectricity.

Here, in one phase detection pixel, the photodiodes 131-1 and 131-3 and the organic photoelectric conversion film 132-1 formed on the left side of the figure are referred to as unit 1, and the unit 1 is formed on the right side of the figure. The photodiodes 131-2 and 131-4 and the organic photoelectric conversion film 132-2 are referred to as unit 2.

When the imaging element 103 has a phase difference detection pixel with the structure shown in FIG. 10, phase difference detection processing is performed using the difference between the output of unit 1 and the output of unit 2.

Specifically, the outputs of the photodiodes 131-1 to 131-4 in the phase detection pixel of FIG. 10 are PhotoDiode1 to PhotoDiode4, and the outputs of the organic photoelectric conversion films 132-1 and 132-2 are Organic1 and Organic1, respectively. Assuming Organic2, the detected phase difference (Phase_Diff) is obtained, for example, by the following equations (12), (13), (14), and (15).

[Formula 12]

[Formula 13]

[Formula 14]

[Formula 15]

In addition, by the following equations (16), (17), and (18), the difference (Phase_Diff_A) of the outputs of the photodiodes 131-1 and 131-2 and the outputs of the photodiodes 131-3 and 131-4 The difference in output (Phase_Diff_B) and the difference in output of the organic photoelectric conversion films 132-1 and 132-2 (Phase_Diff_C) are obtained, and the authenticity of each is determined, so as to obtain any one of Phase_Diff_A, Phase_Diff_B, and Phase_Diff_C. You may use it as a phase difference.

[Formula 16]

[Formula 17]

[Formula 18]

Additionally, since Phase_Diff_A, Phase_Diff_B, and Phase_Diff_C are phase differences for each color component, the color of the light source environment or subject may be determined, and any one of Phase_Diff_A, Phase_Diff_B, and Phase_Diff_C may be used as the phase difference.

Additionally, using at least one or all of the above-described certainty, light source environment, and subject color, weight may be given to Phase_Diff_A, Phase_Diff_B, and Phase_Diff_C to obtain the final phase difference.

In addition, in the above-mentioned equations (12) to (18), PhotoDiode1 to PhotoDiode4 and Organic1 and Organic2 are the photodiodes 131-1 to 131-4 of the phase detection pixel and the organic photoelectric conversion films 132-1 and 132- Although the output value in 2) is set as itself, it can also be set as a value with gain given to each output using a predetermined coefficient.

According to the structure of the phase difference detection pixel shown in FIG. 10, phase difference detection can be performed using the difference in output between a plurality of photoelectric conversion layers, and by not providing a light shielding film or color filter, optical loss is minimized. You can do less. As a result, sufficient SNR can be obtained even in a low-light environment, and phase difference detection can be performed accurately.

In addition, in the phase detection pixel shown in FIG. 10, when manufacturing deviation occurs in the cross-sectional height direction, the output of any one of the plurality of photoelectric conversion layers (for example, photodiodes 131-1 and 131-2) Even if this becomes uncertain, since the output of a different photoelectric conversion layer can be used, it is also possible to ensure robustness against variations in manufacturing.

In addition, in the phase detection pixel shown in FIG. 10, the organic photoelectric conversion film is formed separately. However, as shown in FIG. 11, the organic photoelectric conversion film 141 that is not formed separately may be used.

In addition, in the structure shown in FIG. 11, when the spectral characteristics of the organic photoelectric conversion film 141 are insufficient, a color filter 142 is provided in the lower layer of the organic photoelectric conversion film 141, as shown in FIG. 12. It is okay to have it prepared. Additionally, as shown in FIG. 13, a color filter 142 may be provided instead of the organic photoelectric conversion film 141.

In the above case, the phase difference detection processing is the output of unit 1 made of photodiodes 131-1 and 131-3, and the output of unit 2 made of photodiodes 131-2 and 131-4. This is done using the difference between .

Additionally, the result of adding up the outputs of unit 1 and unit 2 in the above-described phase difference detection pixel is equivalent to the output of a normal imaging pixel. That is, the pixel structures shown in FIGS. 10 to 13 can also be applied to imaging pixels. Therefore, the pixel structure shown in FIGS. 10 to 13 may be applied to all pixels in the imaging device 103.

[Another structural example of a phase detection pixel]

Fig. 14 is a cross-sectional view showing another structural example of a phase difference detection pixel of the present technology.

In the phase detection pixel shown in FIG. 14, organic photoelectric conversion films 151-1 and 151-2 are formed on the upper layer of the semiconductor substrate 121, and organic photoelectric conversion films 152-1 and 152-2 are formed on the upper layer. ) is formed, and organic photoelectric conversion films 153-1 and 153-2 are formed on the upper layer. Additionally, an on-chip lens 126 is formed on the organic photoelectric conversion films 153-1 and 153-2.

Each phase detection pixel shown in FIG. 14 includes one on-chip lens 126 and a plurality of photoelectric conversion layers formed lower than the on-chip lens 126, specifically, an organic photoelectric conversion film (from the upper layer) 153-1, 153-2), organic photoelectric conversion films 152-1, 152-2, and organic photoelectric conversion films 151-1, 151-2. The organic photoelectric conversion films 153-1 and 153-2, the organic photoelectric conversion films 152-1 and 152-2, and the organic photoelectric conversion films 151-1 and 151-2 are respectively formed in segments with respect to the light receiving surface. It is done.

In the phase detection pixel shown in FIG. 14, each photoelectric conversion layer, that is, the uppermost organic photoelectric conversion films 153-1 and 153-2, the second layer from the top, the organic photoelectric conversion films 152-1, 152-2), the organic photoelectric conversion films 151-1 and 151-2 in the third layer from the top photoelectrically convert light of different wavelengths. For example, the organic photoelectric conversion films 153-1 and 153-2 photoelectrically convert green light, and the organic photoelectric conversion films 152-1 and 152-2 photoelectrically convert blue light, and the organic photoelectric conversion films 152-1 and 152-2 photoelectrically convert blue light. The conversion films 151-1 and 151-2 convert red light into photoelectricity.

Even when the imaging element 103 has a phase difference detection pixel with the structure shown in FIG. 14, phase difference detection processing is performed similarly to the phase difference detection pixel with the structure shown in FIG. 10.

In addition, in the phase detection pixel shown in FIG. 14, the organic photoelectric conversion film is formed by dividing all three layers, but as shown in FIG. 15, only the uppermost organic photoelectric conversion films 153-1 and 153-2 are divided. Even if the light-shielding film 161 is provided on the lower layer of the organic photoelectric conversion films 153-1 and 153-2, the light incident on the organic photoelectric conversion films 151 and 152 on the lower layer is partially blocked. good night.

In addition, as shown in FIG. 16, a photodiode 171 formed on the semiconductor substrate 121 is provided in place of the lowest layer organic photoelectric conversion film 151 in the phase difference detection pixel shown in FIG. 15. It's also good.

<2. Second embodiment>

[Configuration of imaging device]

Fig. 17 is a block diagram showing a configuration example of an imaging device according to the second embodiment of the present technology.

The imaging device 300 shown in FIG. 17 includes a lens 101, an optical filter 102, an imaging element 301, an A/D conversion unit 104, a clamp unit 105, and a color mixing subtraction unit 302. , it consists of a demosaicing unit 109, an LM/WB/gamma correction unit 110, a luminance chroma signal generation unit 111, and an I/F unit 112.

In addition, in the imaging device 300 of FIG. 17, configurations having the same functions as those provided in the imaging device 100 of FIG. 1 will be given the same names and reference numerals, and their descriptions will be appropriately omitted. Let's do it.

The imaging element 301 is different from the imaging element 103 provided in the imaging device 100 of FIG. 1 . Phase difference detection pixels are not arranged, but only imaging pixels are arranged. That is, the imaging device 300 performs imaging processing without performing phase difference AF processing.

The color mixture subtraction unit 302 subtracts the color mixture component, which is the light component that passes through the filter of the surrounding pixel, from the image data from the clamp unit 105. The color mixture subtraction unit 302 supplies image data from which the color mixture components have been subtracted to the demosaicing unit 109.

[Structure example of imaging pixel]

Fig. 18 is a cross-sectional view showing a structural example of an imaging pixel of the present technology.

In the imaging pixel shown in FIG. 18, a photodiode 322 as a photoelectric conversion unit is formed on the semiconductor substrate 321. On the upper layer of the semiconductor substrate 321, a light-shielding film 323 and a color filter 324 are formed in the same layer, and an organic photoelectric conversion film 325 is formed on their upper layer, specifically, directly above the light-shielding film 323. It is done. Additionally, an on-chip lens 326 is formed on the organic photoelectric conversion film 325.

Each imaging pixel shown in FIG. 18 includes one on-chip lens 326 and a plurality of photoelectric conversion layers formed lower than the on-chip lens 326, specifically, an organic photoelectric conversion film 325 from the upper layer. ), and is provided with a photodiode 322. The organic photoelectric conversion film 325 is partially formed on the light-receiving surface. Specifically, the organic photoelectric conversion film 325 is formed at a boundary portion with an adjacent imaging pixel, as shown in FIG. 19 . Additionally, the boundary portion of the photodiode 322 with the adjacent imaging pixel is partially shielded from light by the light shielding film 323.

Next, with reference to FIG. 20, the structures of the conventional imaging pixel and the imaging pixel of the present technology are compared.

The conventional imaging pixel shown on the left side of FIG. 20 differs from the imaging pixel of the present technology shown on the right side of FIG. 20 in that the organic photoelectric conversion film 325 is not provided.

According to the structure of a conventional imaging pixel, when the incident light (L) passing through the on-chip lens 326 of the left pixel enters the photodiode 322 of the right pixel, it is possible to detect the amount of light. Because there were no numbers, it was difficult to correct the color mixture component for the output of the pixel on the right. As a result, there is a risk of adverse effects on color reproducibility and SNR.

Meanwhile, according to the structure of the imaging pixel of the present technology, when the incident light L passing through the on-chip lens 326 of the left pixel enters the photodiode 322 of the right pixel, what is the amount of light? can be estimated from the output of the organic photoelectric conversion film 325, and it becomes possible to correct the color mixture component for the output of the pixel on the right.

[About image capture processing]

Next, with reference to the flow chart in FIG. 21, imaging processing by the imaging device 300 will be described.

In addition, since the processing of steps S301 to S303 and S305 to S308 in the flowchart of FIG. 21 is the same as the processing of steps S201 to S203 and S205 to S208 of the flowchart of FIG. 6, their description is omitted. Additionally, in step S203, image data (pixel values) for all pixels from which the black level has been subtracted is supplied to the color mixture subtraction unit 302 by the clamp unit 105.

In step S304, the color mixture subtraction unit 302 performs color mixture subtraction processing, subtracts the color mixture component from the image data from the clamp unit 105, and supplies it to the demosaicing unit 109.

Specifically, the color mixture subtraction unit 302 estimates the color mixture component using the output of the organic photoelectric conversion film 325, and calculates the pixel value (P_Out) of the imaging pixel after color mixture correction as the following equation (19). Saved by

[Formula 19]

In equation (19), PhotoDiode_Out represents the output of the photo diode 322, and Organic_Out represents the output of the organic photoelectric conversion film 325. Additionally, α is a coefficient that is arbitrarily set. For example, the value of α may be adjusted depending on whether the arrangement of the pixel subject to color mixing correction is close to the edge of the angle of view.

In addition, the pixel value (P_Out) of the imaging pixel after color mixing correction is not limited to that obtained by equation (19), and may be obtained by another calculation. For example, calculations may be performed according to the color of the pixel of interest that is subject to color mixture correction, or the output of the photo diode 322 of the imaging pixel adjacent to the pixel of interest may be used in addition to the output of the organic photoelectric conversion film 325. You may allow the calculation to be performed.

The image data from which the color mixture components have been subtracted in this way is supplied to the demosaicing unit 109.

According to the above processing, in the color mixing correction of the imaging pixel, the output corresponding to the color mixed light can be estimated from the output of the organic photoelectric conversion film 325, so correction of the color mixing component for the output of the pixel of interest can be performed. Furthermore, it becomes possible to achieve higher image quality and obtain better images.

In addition, although the organic photoelectric conversion film 325 is formed at the boundary portion of the imaging pixel, it may be formed as one continuous film in the effective pixel area, for example, it may be formed every 2x2 pixels. Additionally, for example, depending on the type of the detected color mixing component, the width at the boundary portion of the imaging pixel of the organic photoelectric conversion film 325, the position at which the organic photoelectric conversion film 325 is formed, and furthermore, the organic photoelectric conversion film 325. You may change the membrane species (material) of (325).

However, in conventional imaging devices, the lighting environment (light source such as a fluorescent lamp or an incandescent light bulb) at the time of imaging is estimated and an image is created according to the lighting environment. However, in recent years, new light sources have been increasing, including LED (Light Emitting Diode) light sources. Meanwhile, in an imaging device in which R pixels, G pixels, and B pixels are arranged in a Bayer array, only three color signals can be obtained, making it difficult to estimate what the light source is.

Therefore, below, an imaging device designed to increase the accuracy of light source estimation will be described.

<3. Third embodiment>

[Configuration of imaging device]

Fig. 22 is a block diagram showing a configuration example of an imaging device according to the third embodiment of the present technology.

The imaging device 400 shown in FIG. 22 includes a lens 101, an optical filter 102, an imaging element 301, an A/D conversion unit 104, a clamp unit 105, and a color mixing subtraction unit 302. , it consists of a demosaicing unit 109, an LM/WB/gamma correction unit 110, a luminance chroma signal generation unit 111, an I/F unit 112, and a light source estimation unit 401.

In addition, in the imaging device 400 of FIG. 22, configurations having the same functions as those provided in the imaging device 300 of FIG. 17 will be given the same names and reference numerals, and their descriptions will be appropriately omitted. Let's do it.

The light source estimation unit 401 estimates the light source illuminating the subject from the RGB data from the demosaicing unit 109 and supplies the estimation result to the LM/WB/gamma correction unit 110.

[About image capture processing]

Next, with reference to the flow chart in FIG. 23, imaging processing by the imaging device 400 will be described.

In addition, since the processing of steps S401 to S405, S408, and S409 in the flowchart of FIG. 23 is the same as the processing of steps S301 to S305, S307, and S308 in the flowchart of FIG. 21, the description thereof is omitted. Furthermore, in step S405, the image data (RGB data) after demosaicing is also supplied to the light source estimation unit 401 by the demosaicing unit 109.

In step S406, the light source estimation unit 401 performs light source estimation on the RGB data from the demosaicing unit 109.

Specifically, the light source estimation unit 401 performs light source estimation using the output of the photo diode 322 and the output of the organic photoelectric conversion film 325 as RGB data for each imaging pixel.

Conventionally, for example, when light source estimation is performed using the output ratios of R/G and B/G, even if there are light sources (A) and light sources (B) with different light source output spectra, the output ratios of R/G and B/G are different. It wasn't limited to being worth it. Specifically, the output of a pixel is not obtained for each wavelength, but is an integral element determined by the product of the spectral characteristics of the imaging device and the light source, etc., so even if the output of each wavelength is different, the integral value is the same. It was not possible to determine the light source.

On the other hand, in the light source estimation unit 401, since new spectral characteristics can be obtained even from the organic photoelectric conversion film 325, for example, even if the R/G and B/G output ratios of the photo diode 322 are the same value, , the spectral characteristics can be divided by the difference in the output of the organic photoelectric conversion film 325, and the accuracy of light source estimation can be improved. In particular, according to the configuration of the imaging device 301, the output from the organic photoelectric conversion film 325 can be obtained without reducing the number of pixels, so the accuracy of light source estimation can be increased without lowering the resolution. .

And the estimation result of the light source estimation performed in this way is supplied to the LM/WB/gamma correction unit 110.

In step S407, the LM/WB/gamma correction unit 110 performs color correction and white balance adjustment on the RGB data from the demosaicing unit 109 based on the estimation result from the light source estimation unit 401. , perform gamma correction. Specifically, the LM/WB/gamma correction unit 110 uses the estimation result from the light source estimation unit 401 to determine matrix coefficients used for color correction or to set a gain for adjusting white balance. Or, determine the gamma curve used for gamma correction.

According to the above processing, light source estimation can be performed using the output of the organic photoelectric conversion film 325 in addition to the output of the photodiode 322, so the accuracy of the light source estimation can be increased, and further, the image By achieving higher image quality, it becomes possible to obtain better images.

Additionally, like the imaging device 450 shown in FIG. 24, the light source estimation unit 401 may be provided in the imaging device 100 (FIG. 1) that performs phase difference detection. According to this configuration, when imaging a bright subject, even if the normal imaging pixels are saturated and the RGB ratio cannot be obtained correctly, the phase detection pixel in which half of the photo diode is light-shielded is not saturated and the RGB ratio can be obtained correctly. , it becomes possible to perform light source estimation with high precision.

In addition, in this case, for example, since new spectral characteristics can be obtained in the organic photoelectric conversion film 125 of the phase detection pixel shown in FIG. 3, the output ratios of R/G and B/G in the photodiode 122 are reduced. Even if the values are equal, the spectral characteristics can be divided by the difference in the output of the organic photoelectric conversion film 125, and the accuracy of light source estimation can be improved. In this way, by using the outputs of a plurality of photoelectric conversion layers with different spectral characteristics, it is possible to perform light source estimation with high precision.

However, the pixel disposed in the imaging element 301 provided in the imaging device that performs color mixing correction is not limited to the structure shown in FIG. 18, and may have a structure as shown in FIG. 25, for example.

[Other structural examples of imaging pixels]

Fig. 25 is a cross-sectional view showing another structural example of an imaging pixel of the present technology.

In Fig. 25, cross sections of mixed color detection pixels (P1, P2) for detecting mixed colors and normal imaging pixels (P3, P4) are shown.

As shown in Fig. 25, in the mixed color detection pixels P1 and P2, a photodiode 522 as a photoelectric conversion unit is formed on the semiconductor substrate 521. A light-shielding film 523 is formed on the upper layer of the semiconductor substrate 521, and an organic photoelectric conversion film 525 is partially formed on the upper layer. Additionally, an on-chip lens 526 is formed on the organic photoelectric conversion film 525.

Additionally, in the imaging pixels P3 and P4, a photodiode 522 as a photoelectric conversion unit is formed on the semiconductor substrate 521. On the upper layer of the semiconductor substrate 521, a light shielding film 523 and a color filter 524 are formed in the same layer, and an on-chip lens 526 is formed on their upper layer.

Each mixed color detection pixel shown in FIG. 25 includes one on-chip lens 526 and a plurality of photoelectric conversion layers formed lower than the on-chip lens 526, specifically, an organic photoelectric conversion film (from the upper layer) 525) and a photodiode 522. The organic photoelectric conversion film 525 is partially formed on the light receiving surface. Additionally, the photodiode 522 is shielded from light on the entire light-receiving surface by the light-shielding film 523.

However, as shown in FIG. 25, a part of the light incident on the imaging pixel P3 enters the photodiode 522 of the mixed color detection pixel P2. That is, the photodiode 522 of the color mixture detection pixel P2 can output only the color mixture component from the adjacent imaging pixel P3. In addition, since the photodiode 522 of the mixed color detection pixel P2 receives light from the adjacent imaging pixel P3, it can be considered to be partially light-shielded.

Therefore, for example, as in the method described in Japanese Patent Application Laid-Open No. 2013-34086, the color mixture subtraction unit 302 of the imaging device 300 in Fig. 17 uses the output of the photodiode 522 of the color mixture detection pixel, and The amount of color mixing in the imaging pixels may be estimated, and the estimated value may be subtracted from the output of the imaging pixels.

In addition, the mixed color detection pixels P1 and P2 shown in FIG. 25 are provided in the imaging element 103 of the imaging device 100 in FIG. 1, and each of the mixed color detection pixels P1 and P2 is an organic photoelectric conversion film ( Phase difference detection may be performed using the difference in the output of 525).

By the way, in the imaging device 103 in FIG. 1, the phase difference detection pixels are arranged interspersed among a plurality of imaging pixels arranged two-dimensionally in a matrix, but all pixels may be used as phase difference detection pixels. In this case, it is necessary to separately provide an imaging device for phase difference AF and an imaging device for imaging in the imaging device.

<4. Fourth embodiment>

[Configuration of imaging device]

Fig. 26 is a block diagram showing a configuration example of an imaging device according to the fourth embodiment of the present technology.

The imaging device 700 shown in FIG. 26 includes a lens 101, an optical filter 102, an AF imaging element 701, an A/D conversion unit 702, a phase difference detection unit 106, and a lens control unit 107. ), imaging device 703, A/D conversion unit 104, clamp unit 105, demosaicing unit 109, LM/WB/gamma correction unit 110, luminance chroma signal generation unit 111, and an I/F unit 112.

In addition, in the imaging device 700 of FIG. 26, configurations having the same functions as those provided in the imaging device 100 of FIG. 1 will be given the same names and reference numerals, and their descriptions will be appropriately omitted. Let's do it.

The AF imaging device 701 is different from the imaging device 103 provided in the imaging device 100 of FIG. 1 . Imaging pixels are not disposed, and only phase difference detection pixels, for example, shown in FIG. 3 are disposed.

The A/D conversion unit 702 converts the RGB electrical signal (analog signal) supplied from the AF imaging device 701 into digital data (image data) and supplies it to the phase difference detection unit 106.

The imaging element 703 is different from the imaging element 103 provided in the imaging device 100 of FIG. 1 . Phase difference detection pixels are not arranged, and only normal imaging pixels are arranged.

According to the above configuration, there is no need to provide phase difference detection pixels in the imaging element 703 used for normal imaging, and therefore there is no need to perform defect correction for the phase difference detection pixels. Additionally, since the AF imaging element 701 and the imaging element 703 can be manufactured separately, they can be manufactured using processes optimized for each.

Additionally, in the imaging device 700 of FIG. 26, the imaging device 301 may be provided instead of the imaging device 703, and the color mixing subtraction unit 302 may be provided to perform the color mixing subtraction process.

In addition, in the imaging device 700 of FIG. 26, an imaging device 701 for AF is provided, but an imaging device for color mixture subtraction or an imaging device for light source estimation may be provided.

In the above-described embodiment, in a configuration in which one pixel includes an organic photoelectric conversion film and a photo diode, the exposure amount (shutter/gain) may be varied for the organic photoelectric conversion film and the photo diode. For example, the frame rate of the photodiode may be set to 30fps, and the frame rate of the organic photoelectric conversion film may be set to 15fps.

In this way, even when the frame rate of the organic photoelectric conversion film is lowered and the accumulation time is lengthened, the normal output from the photodiode is not affected.

Additionally, in the above-described embodiment, exit pupil correction may be performed by applying shrinkage to the on-chip lens or color filter of each pixel of the imaging device. This makes it possible to correct shading and improve sensitivity.

In addition, the imaging element of the present technology is not limited to the above-mentioned imaging device, and can also be provided in other electronic devices having an imaging function.

In addition, the embodiment of the present technology is not limited to the above-described embodiment, and various changes are possible without departing from the gist of the present technology.

Additionally, this technology can have the following configuration.

(One)

An imaging device having a plurality of pixels,

The pixel is,

One on-chip lens,

A plurality of photoelectric conversion layers formed below the on-chip lens,

An imaging device wherein at least two of the photoelectric conversion layers among the plurality of photoelectric conversion layers are respectively formed separately, partially formed, or partially shielded from light with respect to the light-receiving surface.

(2)

The imaging device according to (1), wherein the pixel is a phase detection pixel for performing AF (Auto Focus) by phase difference detection.

(3)

The imaging device according to (2), wherein the difference in output between the photoelectric conversion layers in the plurality of phase difference detection pixels is used for phase difference detection.

(4)

Also comprising imaging pixels for generating an image,

The imaging device according to (2), wherein the phase difference detection pixels are arranged interspersed among the plurality of imaging pixels arranged two-dimensionally in a matrix.

(5)

The imaging device according to (4), wherein the difference between the outputs of the photoelectric conversion layer in the phase difference detection pixel and the imaging pixel disposed around the phase difference detection pixel is used for phase difference detection.

(6)

The phase detection pixel is,

A partially formed organic photoelectric conversion film as the uppermost photoelectric conversion layer among the plurality of photoelectric conversion layers;

The imaging device according to any one of (2) to (5), wherein the photoelectric conversion layer is formed on a substrate lower than the organic photoelectric conversion film, and includes a photoelectric conversion portion that is partially light-shielded.

(7)

The phase difference detection pixel further includes a light-shielding film under the organic photoelectric conversion film that partially blocks light from the photoelectric conversion unit,

The imaging device according to (6), wherein the organic photoelectric conversion film photoelectrically converts light partially blocked by the light shielding film.

(8)

The imaging device according to (2), wherein the phase difference detection pixel includes, as the plurality of photoelectric conversion layers, at least two layers of divided photoelectric conversion portions formed on a substrate.

(9)

The imaging device according to (2), wherein the phase difference detection pixel includes, as the plurality of photoelectric conversion layers, at least two layers of organic photoelectric conversion films that are divided or partially shielded from light.

(10)

The imaging device according to (1), wherein the pixel is an imaging pixel for generating an image.

(11)

The imaging pixel is,

A partially formed organic photoelectric conversion film as the uppermost photoelectric conversion layer among the plurality of photoelectric conversion layers;

The photoelectric conversion layer is formed on a substrate lower than the organic photoelectric conversion film, and includes a photoelectric conversion portion in which a boundary portion with another adjacent imaging pixel is partially shielded from light,

The imaging device according to (10), wherein the organic photoelectric conversion film is formed at a boundary portion with the other imaging pixel.

(12)

The phase difference detection pixel includes a plurality of photoelectric conversion layers, an organic photoelectric conversion film, and a photoelectric conversion unit formed on a substrate,

The imaging device according to (1) to (11), wherein the organic photoelectric conversion film and the photoelectric conversion unit are each controlled to have different exposure amounts.

(13)

An imaging device having a plurality of pixels,

The pixel is,

One on-chip lens,

A plurality of photoelectric conversion layers formed below the on-chip lens,

An imaging element in which at least two of the plurality of photoelectric conversion layers are divided, partially formed, or partially shielded from the light-receiving surface, respectively;

An electronic device including a lens that makes subject light incident on the imaging device.

(14)

a phase difference detection unit that performs phase difference detection using differences in output between the photoelectric conversion layers in the plurality of pixels;

The electronic device according to (13), further comprising a lens control unit that controls driving of the lens in response to the detected phase difference.

(15)

The pixel is,

A partially formed organic photoelectric conversion film as the uppermost photoelectric conversion layer among the plurality of photoelectric conversion layers;

The electronic device according to (14), wherein the photoelectric conversion layer is formed on a substrate lower than the organic photoelectric conversion film, and includes a photoelectric conversion section that is partially light-shielded.

(16)

The electronic device according to (15), further comprising a defect correction unit that corrects the output of the photoelectric conversion unit as a pixel value for generating an image, using the output of the organic photoelectric conversion film.

(17)

The pixel is,

A partially formed organic photoelectric conversion film as the uppermost photoelectric conversion layer among the plurality of photoelectric conversion layers;

The photoelectric conversion layer is formed on a substrate lower than the organic photoelectric conversion film, and includes a photoelectric conversion portion in which a boundary portion with another adjacent pixel is partially shielded from light,

The electronic device according to (13), wherein the organic photoelectric conversion film is formed at a boundary portion with the other pixel.

(18)

The electronic device according to (17), further comprising a color mixture subtraction unit that subtracts a color mixture component from the output of the photoelectric conversion unit as a pixel value for generating an image, using the output of the organic photoelectric conversion film.

(19)

The electronic device according to any one of (13) to (18), further comprising a light source estimation unit that estimates a light source of the object light using outputs of the plurality of photoelectric conversion layers having different spectral characteristics.

(20)

The electronic device according to (19), further comprising a color characteristic correction unit that corrects the color characteristics of the pixel value output from the photoelectric conversion unit based on the estimation result of the light source estimation unit.

100: imaging device
101: lens
103: imaging device
106: Phase difference detection unit
107: Lens control unit
108: defect correction unit
110: LM/WB/gamma correction unit
122: photodiode
123: light shield
125: Organic photoelectric conversion film
300: imaging device
301: imaging device
302: color mixing subtractor
322: photodiode
323: shade curtain
325: Organic photoelectric conversion film
400: imaging device
401: Light source estimation unit
450: imaging device

Claims (18)

A first photoelectric conversion unit disposed on a semiconductor substrate,
a second photoelectric conversion unit disposed on the semiconductor substrate;
a color filter disposed on the semiconductor substrate and below at least one of the first photoelectric conversion unit and the second photoelectric conversion unit;
Provided with a photo diode disposed in the semiconductor substrate,
configured to detect a phase difference from at least one of a first output of the first photoelectric conversion unit and a second output of the second photoelectric conversion unit,
When viewed in plan, the color filter is disposed between the first photoelectric conversion unit and the second photoelectric conversion unit, and does not overlap the first photoelectric conversion unit and the second photoelectric conversion unit. A photodetection device that According to paragraph 1,
The photo diode is a light detection device characterized in that it receives light passing through the color filter. According to paragraph 1,
The photodiode is configured to photoelectrically convert light of a different wavelength from the at least one of the first photoelectric conversion unit and the second photoelectric conversion unit. According to paragraph 1,
Further provided with a light-shading portion,
A photodetector, wherein at least a portion of the light blocking portion is disposed on the same layer as the color filter when viewed in cross section. According to paragraph 4,
A light detection device, wherein the light blocking portion is made of metal. According to paragraph 1,
a first on-chip lens corresponding to the first photoelectric conversion unit;
A photodetector device further comprising a second on-chip lens corresponding to the second photoelectric conversion unit. According to paragraph 1,
A photodetector, characterized in that the first photoelectric conversion unit and the second photoelectric conversion unit are configured to photoelectrically convert light having the same wavelength. In clause 7,
A light detection device, characterized in that the light is green light. In clause 7,
A light detection device, characterized in that the light is blue light. In clause 7,
A light detection device, characterized in that the light is red light. In clause 7,
A light detection device, characterized in that the light is white light. In clause 7,
A light detection device, characterized in that the light is infrared light. In clause 7,
A light detection device, characterized in that the light is ultraviolet light. According to paragraph 1,
a first electrode disposed below the first photoelectric conversion unit and above the semiconductor substrate;
Further comprising a second electrode disposed below the second photoelectric conversion unit and above the semiconductor substrate,
The planar area of the first photoelectric conversion unit is equal to the planar area of the first electrode,
A photodetector, characterized in that the planar area of the second photoelectric conversion unit is the same as the planar area of the second electrode. According to paragraph 1,
A photodetector device further comprising an on-chip lens corresponding to the photodiode and at least one of the first photoelectric conversion unit and the second photoelectric conversion unit. According to clause 15,
When viewed from a plan view, the on-chip lens overlaps the at least one of the first photoelectric conversion unit and the second photoelectric conversion unit, the color filter, and the photo diode. According to paragraph 1,
A photodetector, wherein the first photoelectric conversion unit is disposed on the same layer as the second photoelectric conversion unit when viewed in cross section. With a lens,
Equipped with a light detection device,
The photodetection device is,
A first photoelectric conversion unit disposed on a semiconductor substrate,
a second photoelectric conversion unit disposed on the semiconductor substrate;
a color filter disposed on the semiconductor substrate and below at least one of the first photoelectric conversion unit and the second photoelectric conversion unit;
Provided with a photo diode disposed in the semiconductor substrate,
configured to detect a phase difference from at least one of a first output of the first photoelectric conversion unit and a second output of the second photoelectric conversion unit,
When viewed in plan, the color filter is disposed between the first photoelectric conversion unit and the second photoelectric conversion unit, and does not overlap the first photoelectric conversion unit and the second photoelectric conversion unit. A light detection device that